System and method for providing emission mammography

Abstract

A system and method for providing emission mammography are provided. The system includes a first gamma emission detector and a second gamma emission detector. The first and second gamma emission detectors are configured to compress an object therebetween. The system further includes a radioactive transmission source. At least one of the first and second gamma emission detectors is configured to detect gamma ray photons from the radioactive transmission source.

What is claimed is: 
     
       1. A medical imaging system comprising:
 a first cadmium zinc telluride (CZT) gamma detector; 
 a second CZT gamma detector, the first and second CZT gamma detectors configured to compress an object therebetween to immobilize the object and detect emission photons; and 
 a gantry configured for rotation, the gantry further configured to support the first CZT gamma detector, the second CZT gamma detector and a transmission source, the gantry providing variable positioning of the first CZT gamma detector, wherein the first CZT gamma detector is coupled to the gantry and configured for movement along the gantry and the second CZT gamma detector is fixedly held to the gantry. 
 
     
     
       2. A medical imaging system in accordance with  claim 1  wherein the transmission source comprises a line source. 
     
     
       3. A medical imaging system in accordance with  claim 1  wherein the transmission source is a line source that is translatable across a face of one of the first gamma detector and second gamma detector. 
     
     
       4. A medical imaging system in accordance with  claim 1  wherein the transmission source is a flood source. 
     
     
       5. A medical imaging system in accordance with  claim 1  further comprising a receptacle configured to store the transmission source therein. 
     
     
       6. A medical imaging system in accordance with  claim 1  further comprising a calibration source. 
     
     
       7. A medical imaging system in accordance with  claim 1  wherein the gantry is configured to rotate to provide medio-lateral and cranio-caudad imaging. 
     
     
       8. A medical imaging system in accordance with  claim 1  wherein the first and second gamma detectors comprise gamma cameras. 
     
     
       9. A medical imaging system in accordance with  claim 1  wherein the object is a human breast and the first and second gamma detectors are configured to provide mammography imaging. 
     
     
       10. A medical imaging system in accordance with  claim 1  further comprising a memory and wherein a compression position of the first gamma detector is stored in the memory. 
     
     
       11. A medical imaging system in accordance with  claim 1  wherein each of the first CZT gamma detector and the second CZT gamma detector having a substantially rectangular polyhedrally shaped body. 
     
     
       12. A medical imaging system in accordance with  claim 1  wherein the emission photons comprise one of photon pairs for positron emission tomography (PET) imaging and single photons for single photon emission computed tomography (SPECT) imaging. 
     
     
       13. A medical imaging system in accordance with  claim 1  wherein the first and second CZT gamma detectors are configured to compress the object therebetween without a compression plate. 
     
     
       14. A medical imaging system in accordance with  claim 1  wherein the second CZT gamma detector is not capable of movement with respect to the first CZT gamma detector. 
     
     
       15. A medical imaging system in accordance with  claim 1  wherein the second CZT gamma detector is not capable of translating along the gantry towards or away from the first CZT gamma detector. 
     
     
       16. A quantitative emission mammography conjugate-view imaging system comprising:
 a first gamma detector coupled to a gantry and configured for movement along the gantry; 
 a second gamma detector fixedly held to the gantry, the first gamma camera variably positionable with the movement to compress a breast between the first gamma detector and the second gamma detector to immobilize the breast therebetween; 
 a translatable radioactive transmission source, at least one of the first and second gamma detectors configured to detect gamma ray photons from the radioactive transmission source; 
 a shielded receptacle for storing the translatable radioactive transmission source; and 
 a calibration source coupled generally along an end of a field of view of the first and second gamma cameras. 
 
     
     
       17. A quantitative emission mammography conjugate-view imaging system in accordance with  claim 16  wherein the transmission source is one of a line source and a flood source. 
     
     
       18. A quantitative emission mammography conjugate-view imaging system in accordance with  claim 16  wherein the first and second gamma detectors comprise solid-state detectors. 
     
     
       19. A method for performing diagnostic imaging, the method comprising:
 detecting emission photons utilizing a first cadmium zinc telluride (CZT) gamma detector and a second CZT gamma detector, the first and second CZT gamma detectors configured to compress an object therebetween to immobilize the object, wherein the first CZT detector is movable relative to a gantry and the second CZT gamma detector is fixedly held to the gantry; and 
 detecting transmission photons from a radioactive transmission source utilizing the first and second CZT gamma detectors. 
 
     
     
       20. A method in accordance with  claim 19  further comprising translating the radioactive transmission source. 
     
     
       21. A method in accordance with  claim 19  further comprising configuring a gantry for rotation and to support the first CZT gamma detector, the second CZT gamma detector and the transmission source, the gantry providing variable positioning of the first CZT gamma detector. 
     
     
       22. A quantitative emission mammography conjugate-view imaging system comprising:
 a first gamma camera coupled to a gantry and configured for translation relative to the gantry; 
 a second gamma camera fixedly held to the gantry, the first gamma camera variably positionable with the translation to compress a breast between the first gamma camera and the second gamma camera; and 
 a processor, configured to receive a first emission image from the first gamma camera and a second emission image from the second gamma camera and calculate quantitative distribution of radiopharmaceutical isotope in the breast based on the received first and second images and the thickness of the lightly compressed breast. 
 
     
     
       23. A quantitative emission mammography system in accordance with  claim 22  wherein the calculation of in vivo activity for a quantitative distribution A of radiopharmaceutical isotope in the breast comprises using the equation:
     A =( C   1   *C   2 ) 1/2 /( x*T*F   1/2 ) 
 wherein, C1 and C2 are the photon counts in the first and second images respectively, x is a calibration factor converting from a measured count rate to activity measured in air, T is a photon acquisition time and F is a fraction of photons transmitted through the imaged breast region containing a lesion. 
 
     
     
       24. A quantitative emission mammography system in accordance with  claim 23  further comprising a transmission source and wherein the fraction F of photons transmitted through the imaged breast region containing the lesion is measured using the transmission source. 
     
     
       25. A quantitative emission mammography system in accordance with  claim 23  wherein the fraction F is calculated from the attenuation coefficient of the breast and the thickness of the lightly compressed breast. 
     
     
       26. A quantitative emission mammography system in accordance with  claim 23  further comprising a calibration source and wherein the calibration factor x is measured using the calibration source. 
     
     
       27. A quantitative emission mammography system in accordance with  claim 23  wherein the quantitative distribution of radiopharmaceutical isotope in the lesion is corrected for self absorption using the equation:
     A′=A *(Sin  h[u*t/ 2])/( u*t/ 2) 
 wherein u is an attenuation coefficient of the breast and t is the thickness of a lesion within the breast.